A conventional mobile satellite antenna system requires a proper satellite tracking unit for adjusting the orientation of an antenna in a satellite direction for receiving signals from a satellite with the conventional mobile satellite antenna system mounted at a movable carrier. In order to adjusting the orientation of the antenna, the conventional mobile satellite antenna system generally has an electrical adjusting structure that includes a plurality of antennas, an active channel connected to the plurality of the antennas and including a phase shifter for forming a transmitting and receiving beam, and an additional active channel having an additional phase shifter for forming and adjusting a satellite tracking beam.
However, the electrical adjusting structure of the mobile satellite antenna system requires a high manufacturing cost and an expensive maintenance cost due to expensive parts such as a phase shifter. Since the electrical adjusting structure of the mobile satellite antenna system is complicated, there are many difficulties arisen to manufacture the mobile satellite antenna system. Furthermore, it takes such a long time to manufacture the mobile satellite antenna system.
Also, the electrical adjusting-type mobile satellite antenna system requires complicate mechanism for diagnosing and maintaining each of parts and functions when the electrical adjusting-type mobile satellite antenna system generates errors or becomes malfunctioned. Especially, the structure of the electrical adjusting-type mobile satellite antenna system becomes more seriously complicated for accurately adjusting the orientation of the beam and removing the phase error of receiving signal.